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Level Crossing Road Traffic Lights

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Level Crossing Road Traffic Lights

Unread postby scarpa » Sat Feb 3, 2018 4:41 pm

Across the UK, Network Rail have replaced all the road traffic lights, nicknamed Wig Wags, with LED type units. Unless anyone knows differently! Are Heritage railways, if they have level crossings, required to carry out replacement with LED type road lights?
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Re: Level Crossing Road Traffic Lights

Unread postby John Webb » Sat Feb 3, 2018 6:19 pm

I don't know about 'Required', but HRA issued "Operating and Safety Matters Issue 10 - December 2016" recommending to their members that such conversions should be done. This followed the issuing by RAIB of a Safety Digest following the collision at Yafforth level crossing on the 3rd of August, 2016. (See https://www.gov.uk/government/publications/yafforth-safety-digest/collision-at-yafforth-level-crossing-3-august-2016 for the details.)

The HRA document concludes its recommendation by pointing out the advantage of road users being faced with similar signals at LCs regardless of ownership of the same.
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Re: Level Crossing Road Traffic Lights

Unread postby Mike Hodgson » Sat Feb 3, 2018 9:25 pm

If you're crossing a public highway, highway signage need to conform to current highway requirements. I believe this includes wig-wags, so you wouldn't get away with (for example) the pre-Hixon version without an amber aspect, but I don't think LEDs are a requirement. The report John cites says

"This accident illustrates the importance of:

road traffic signals at level crossings being visible and sufficiently conspicuous to draw the attention of approaching road users
replacing 36 Watt incandescent lamps in level crossing road traffic signals with lamps that have a higher level of brightness, such as modern LEDs
infrastructure managers giving careful consideration to the factors which influence user behaviour at level crossings without barriers and the potential value of installing barriers at higher risk locations
appropriate competency management arrangements for staff maintaining safety critical equipment."

That wording seems to imply that filament bulbs are still OK provided they are powerful enough in the circumstances - a problem at Yafforth being poor visibility. In practice it's probably easier to comply with the RAIB's recommendation to use LDEs rather than make a safety case justifying not doing so.
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Re: Level Crossing Road Traffic Lights

Unread postby Richard Lemon » Sat Feb 3, 2018 9:35 pm

The HRA recommends. That is the relevant word. John Webb correctly points out that a road user does not care whose railway it is, but rightly expects consistency.

The HRA cannot enforce, that is the role of the ORR. However, the ORR will normally expect HRA Guidance to be followed, unless there is good reason otherwise.
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Re: Level Crossing Road Traffic Lights

Unread postby John Webb » Sun Feb 4, 2018 8:50 am

Out of curiosity, is it simply a matter of replacing a 36W bulb with an LED equivalent, replacing the complete lamp units, or does the entire 'wig-wag' have to be changed?
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Re: Level Crossing Road Traffic Lights

Unread postby ex Probationer » Sun Feb 4, 2018 5:35 pm

I believe that over the years, the improved standards for crossing light and lamp proving circuits have not required retospective upgrading. Many of the original 24v 36w warning light clusters only had one red lamp proving relay for each side of the crossing. I think it was in the late 1980s, a risk based approach caused many AHB, ABCL & AOCL crossing light clusters to be provided with improved red lamp proving circuits for each light cluster and some were upgraded to 24v 50w Halogen units to improve light output. I don't think many existing MCB crossing light units were upgraded at that time. Since the late 1980's all new crossings were provided with 24v 50w Halogen lamp units until the recent changes to LED units. The latest standards call for improved light output, which are met by the new LED lamp clusters, they require a new flasher unit, as well as new lamp proving relays, all are needed to be changed together.
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Re: Level Crossing Road Traffic Lights

Unread postby LlaniGraham » Fri Feb 9, 2018 2:57 pm

John Webb wrote:Out of curiosity, is it simply a matter of replacing a 36W bulb with an LED equivalent, replacing the complete lamp units, or does the entire 'wig-wag' have to be changed?


I should imagine it is a bit more than just changing the "bulb" since generally the flashing rate is dependent on the resistance of the light unit, and an LED's is much lower than the 36w normal bulb. For example, if you put an LED repalcement in the flasher on your car they will flash at a much greater speed, so you have to either replace the flasher unit or add a resistor to that "bulb".
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